Web centerline control device



Jaln. 19, 1954 J, C, FROMMER 2,666,639

WEB CENTERLINE CONTROL DEVICE Filed May 14, 1951 l 3 sheets-sheet 1 FIG. Z.

INVENToR. JosEpy C FROMMER BY ga/MM ATTORNEY Jan- 19, 1954 J. c. FROMMER WEB CENTERLINE CONTROL DEVICE 3 Sheets-Sheet 2 Filed May 14, 1951 INVENTOR.

L/bJfPH C. EPO/wm@ ATTORNEY Jan. 19, 1954 Q FRQMMER 2,666,639

WEBy CENTERLINE CONTROL DEVICE Filed May 14, 1951 3 Sheets-Sheet 5 220 VaL 7s l/a Mars INVENTOR. FIG. 5 JOSEPH CZ FRONMR M Q'wzwwvz Hr rom/EY Patented Jan. 19, 1954 WEB cEN'rERLINE CONTROL DEVICE Joseph C. Frommer, Cincinnati, Ohio, assigner to Electric'Eye Equipment Company, Danville, Ill., a corporation of Delaware Application May 14, 1951, Serial No. 226,158

5 claims. (o1. svi-2.6)

This invention relates generally to a method and device for centering a moving web in order to control an operation thereon. More specifically, it relates to a device used to detect the lateral position of a continuous moving web of paper as it travels through a printing press, and to initiate corrections which will cause the centerline (that is, the line midway between the two edges) of the web to be returned to a constant position relative to the press frame or other fixed point of reference.

While the device is specically useful on a multi-color printing press which prints on a paper web, it can be used as well on any machine carrying a continuous web, and will control any solid web material, opaque or transparent, such as cellophane, plastic, metal, coated cloth, and the like and maintain such webs centered on a predetermined reference line or point.

In one important embodiment oi my invention the detecting portion of the device comprises two scanners, one located at each edge of the web. These scanners detect the location of the web to operate a control circuit in such away that, if there is any variation in the width of the web, the scanners move together or apart to adapt themselves to the change in width.

If the web moves sidewise, the scanners detect this fact, and operate a control circuit which will cause an aligning means, such as a set of pivoted rolls to operate to return the web to its proper position. There are many different types of aligning means in common use, and this description does not apply to any particular means, but works equally well with any of them. My invention is in the centering of a web regardless of variation A in width by moving the two scanners to always stay symmetrically with respect to the desired centerline and to follow the width of the web, and this has hitherto not been accomplished.

My invention can be further understood by referring to the drawings. These drawings represent details of a system using pneumatic scanners andv electrical control circuits. In these drawings:

Fig. l is a general view of the mechanism used to detect the position of the web.

Fig. 2 is a cross-section view of part of one of the scanners, showing the relation of the edge ofthe web to an air orifice and a vane switch.

Fig. 3 is a cut-away perspective view showing the relation of the scanner positioning electric motor, and the gears and position screw operatedv by the motor.

Fig. 4 is a partial view of the scannerzshowrlg the relative'location of the four air orifices of one scanner.

Fig. 5 is a wiring diagram Ashowing the basic parts vofthe electricalcircuit.

Referring to Figures l and 2, the web I, with edges Iwand-Ibris shown as moving in the direction of the arrow, through a machine having frame sides 2 and 3- The scanners 4 and 5 are supported by a square metal bar 6, which in turn is supported by bracketassemblies and 8, attached to the machine frame sides 2 and 3 by screws; Clamp blocks 9 and I0 are rigidly fastened to bar 6, while scanners 4 and 5 are free to slide lon bar 5 andare located on this bar by positioning screws I I and I2, whichengage female threads tapped into clamp blocks 9 and I Il.

Referring to Figure 3, a cut-away view of part of scanner 4 shows a reversible electric motor I3, mounted within scanner 4 on bracket I 4. Gear I5 isvfastened to the output shaft of motor I3, and meshes with gear I6 attached to positioning screw I I. Rotation of the motor output shaft thus causes rotation of the positioning screw II andthis causes movement of the scanner 4 toward or away from the web, depending on the direction of rotation of the motor. A similar motor and gear train are enclosed in scanner 5 to cause rotation of screw I2. The electric motors in both scanners 4 and 5 are wired in parallel, so that they operate at the same time, and their direction of rotation is such that the scanners simultaneously move toward the web, or close, or else they both move away from the center of the web, or spread.7`

To make sure the scanners always remain equi- Idistant Yfrom the desired centerline, and are not allowed to vary their location due to minute but cumulative diiierences in speed or deceleration, the scanners are connected mechanically by gearing and a spline bar. Referring to Figure 3, gear II is an idler which transmits motion from gear I5 toY I8, thence to shaft I9 and gear 20, which drives gear 2| having a square hole 22 in its center. A square spline bar 23 passes through `this hole and is caused to rotate by the rotation of gear 2|. This bar 23 is also shown in Figure 1. A similar gear train exists in scanner 5. lhus it will be seen that one revolution of positioning screw I I must be accompanied by exactly one revolution of positioning screw I2, since screws II and I2 are mechanically connected by gearing and by spline bar 23.V A collar 24 is fastened to each end ofbar 23 Vto prevent bar 23 from sliding out of the square hole 22.

Referring to Figures l and 2, compressed air striking vane 33 causes it to move to a stop 35 and operate switch 31. Orices 28, 29, 3U and 3'1 are arranged on a diagonal line,vrelative to the edge of the web, so that when the edge of the web is in normal position, orific'esZ'and 29 are covered, and orices 33 and 3 l'a'r'euncovered. In

this normal position, vanes 34 and 35 are down,

and vanes 32 and 33 are heldl against stop- 36* by air from orices 3l and 30, If the edge of the web moves to cover orice 30, vane 33 wllmove away from stop 35, due to spring action within switch 31, andcon'tacts' will closewithinswitch 31. I f the edge of the web moves to uncoveriorice'29, vane 34 will b'eiorced against stop 36 by air from orice 29,an'd this will close contacts within the switch attached to' vane 34. Each of the four Vanes in each'scanne'r operates an individual switch, and each switch is wired in such a manner that when the web is in normal position, the switch contacts are open. A hole 38 is pro'- vided in each scanner', to allow air from passager 21 to be admitted to the interior of the scanner, pressurizing it and retarding the entrance of dirt from the atmosphere.vr

I have described compressed air detecting means but it is to be understood that other detecting means such as electrical contacts, magnetic means, photoelectric devicesy and the like can also be used. y

In the wiring diagram (Figure) all switches and relays are shown in condition in'which they would be found when the' web isi running in its normal position, i. e., with orifices 3l) and 3| in scanner and the corresponding orifices in scanner l uncovered. Thus, the switches are all open and the relays cle-energized.

Referring to Figure 5 andFigure 1, vane 32 operates switch 39, vane 33 operates switch 31, vane 3A operates switch 43, and vane'35 operates switch 4l, all on scanner 5. On scanner 4, vane 42 operates switch 55, vane 43 operates switch 41, vane 43 operates switch 48, and vane 45 operates switch lle.

Switches 31, dil, 41, andv 43 determine thedi-Y rection and type of correction while switches 39, tl, 45 and 49 affect the speed of web corrections. Four corrections maybe caused 'to` occur. The scanners may close. The' scanners may spread. The web may be moved toward scanner 5. The web may be moved toward scanner'5;

To further illustrate my invention, the operation of my device is described if lthe edges of the web move from their nori'nalpsition.- A movement causing one of the switches'to depart from its normal position is referred to as violation.

The physically possible violations are listed below. In addition to they violations listed, there are several other possibilities. These may be found by taking all the possible combinations of switches 31, lli, 31, and 48. v These violations cannot take place, however, when the system is operating properly. Y

A. If vane 33 falls, switch 31 closes. This causes relay 5B to be energized, which closes contacts 5l and 52 and opens contact 53. When contact 52 closes, relay 54 isenergizedand closes Y switches 4I! and 41 both close.

contact 55. This energizes the reversible scanner motors I3 and l'and causes them to run in such a direction that the scanners spread.

B. If vane 44 falls, switch 43 closes. This energizes relay 55 which causes contacts 5l and 58 to close and contact 55 to open. When contact 58 closes, relay 53 is energized and contact 55 closes. This again causes the'motors -l 3'and 1li to run in such a direction that the scanners spread.

C. If vane 34 is caused to rise by air from orice 29, switch di! will close and energize relay B3 which will'cause contacts ti and B2 to close and contact 63 to open. When contact 5t closes,

relayllf is energized and contact 55 is closed. The closing of contact 55 energizes the scanner motors l'and 1c' and causes them to run in such a direction thaty the scanners close.

D. If cane 43 is caused to rise, switch 31 will clo'seand energize relay E6 which will cause contacts 51 and 68 to closeand contact 3Q to open. Whencontact BS'closes, relay 511 is energized and contact' 55' isclosed. The closing of contact 55 energizes the scanner motors i3 and 'it and causesthem to run in such a direction that the scannersy close.

E. If Vanes 33 and Lid both fall, switches 31 and43bo'th close. Relays 55 and 56 are energized, closing contacts 5 I, 52, 51, and 58 and open ing contactsr53 and 59. This completes the circuit through contacts'z, 53, 33and 5S and energizes relay 5e. Contact 55 again closes and causesthe scanner motors i3 and 1Q to run and the scanners l to spread.

Iffvane's 34l and 43 are both caused to rise, Relays 53 and 55 arie energizedclosing contacts 5i, 52, 3l, and 5S and-opening-contacts 53and 63. This completes the'V circuit through contacts 62, 58, 53, and 55 and energizes relay 54. Contact t5 closes and causes the 'scanner motors i3 and 1E to run and thefs'cannersto close;

G. If vane 33` falls and vane 43 rises, switches 31Y and 41v will close and energize relays 55 and 66. Contacts 5l, 52, 51 and 53 will close and contacts 53 and 33 will open. Contacts 53 and 59 open the circuits torelays 5e and 55, respectively, so that the closing of contacts GB and 52 will not cause thescanner motors to operate. Contacts 5I and 31 are wired in series with relay 1l, and this relay is therefore energized. Contacts 12 and 13 are closed'. When contact 13 is closed. the circuit` to solenoid valve 113 is completed. Energizing thefsolenoid'l14 causes the compensating mechanism to move the web toward scanner 4.

H. If vane 34 rises and vane lil falls, switches 40 and 48 will close and energize relays 6G and 5B. Contacts 6l, 32, 51, and 58 will close and contacts 63 and 59 will open. Contacts 63 and 59 open the circuits to relays 5d and 53 respectively,'s'o that the closing of contacts 53 and 62 will not cause the scanner motors to operate. Contacts! 6|"an'd 51 are wired in series with relay 15, and this relay is therefore energized. Contacts 15 and 11 are closed. When contact 'il is closed, the circuit to solenoid valve 18 is completed. Energizing the solenoid 18 causes the compensating Inchanism to move the web toward scanner 5.

I. Ifone or more of the switches 39, dl, 4E and 43 close, the circuit torelay '13 will be completed. Whenrelay 19 is energized, contact 33 closes. If compensation isA takingv place when relay 15 is energized, i.4 e.,` if either relay l! or relay 65 is energized at the same time, the circuit to soleno'id valve 8l.islcompletedvthrough contacts 12 and 83 or through contacts 16 and 8S. Energizing solenoid -valve 8l causes an increase in the rate of compensation. For example, if hydraulic compensating motors are used, solenoid valve SVI (when it is energized) increases the rate of ow of oil through these motors. The closing ofone or more of these switches does not increasef'the rate at which the scanners close or spread.

The violations listed under A and B above indicate that the web has become wider and also is oii" center. The scanners Vare first caused to spread, and by so doing will give an indication causing the web to be moved in the proper direction to center it. With the connections as shown, the positioning of the scanners is rst corrected, and after this move is completed, the web is properly positioned. By rearranging the relay contacts, it is possible to reverse this sequence and compensate rst, with the scanner adjustment taking place when compensationy is cornpleted. Another connection makes it possible to make both corrections simultaneously.

The violations listed under C and D above indicate that the web has become narrower and also is 01T center. The scanners are rst adjusted to the new web width and, when so adjusted, will give an indication which will cause the web to be centered. As in the caseV of a wider web, the order of these corrections may be reversed or both may be accomplished at once by a change in the wiring of the relays.

A pulsing amplier may be used in conjunction with this system to give a pulsing compensation. In this case, relays 'H and 'l5 are energized ulsating by placing the contacts of a pulsing relay in series with the coils of these relays. The pulsing relay coil is energized and cle-energized at the proper rate by being connected in the plate circuit of the pulsing amplifier. f This ampliiier is a special multivibrator-type circuit. When it is used in conjunction with this system, an increased rate of compensation is obtained by using relay 'I9 to change the amount of resistance in the grid circuit of one of vthe multivibrator tubes.

Referring to Figure 1, the operation of the system may be summarized as follows: When one or both of Vanes 33 and 44 are caused to fall, the scanners spread. When one or both of vanes 34 and 43 are caused to rise, the scanners close. When vane 33 falls and vane 43 rises, the web is .moved toward scanner 4. When vane 34 rises and vane 44 falls, the web is moved toward scanner 5. When one or more of vanes 32, 35, 42, and G depart from their normal positions, the web compensation rate is increased.

I claim:

1. A device for centering a moving web varying in width along a longitudinal center-line comprising signal sending means positioned ad jacent each edge of` said web, signal receiving means positioned with respect to said web and said signal sending means so as to be responsive to the transverse position of the edges of said web with respect to said signal sending means, means adjusting the distance between said signal sending means disposed on each side of the web along a line generally transverse to said center line, means responsive to signals received by either or both of said signal receiving means controlling said width adjustment of said signal sending means in accordance with varying widths in said web independent of the centering of said web, and means responsive to signals received by both of said signal receiving means indicating the center of said web relative to said centerline.

2. The device of claim 1 further defined by means for initiating the movement of said web laterally in response to signals received by said signal receiving means thereby maintaining said center of said web substantially on said center line.

3. A device for keeping a web in center position with respect to a xed center line comprising two exploring heads having each at least one reference means sensitive to lateral displacement of the edge of said web with respect n to said means and positioned near the two edges of said web, means responsive jointly to signals from each of said exploring heads indicating lateral displacement of said edges of said web in directions non-opposite to each other and including means for initiating lateral movement of said web, and means responsive jointly lto signals from either or both of said exploring heads indicating lateral displacement of said edges of said web in directions opposite to each other and including means to move said two vexploring heads simultaneously and symmetrically with respect to said centerline.

4. The device of claim 3 further defined in that said reference means is operated in response to pneumatic pressure.

5. A device for centering a moving web varying in'width along a longitudinal centerline comprising signal sending means positioned adjacent each edge of said web, said signal sending means comprising a' scanner provided with. four orices arranged on a diagonal line relative to the `edge of said web and positioned so that when the edge of said web is in normal position said web covers two of said orifices and including means for admitting compressed air to said orifices, signal receiving means positioned with respect to said web and said signal sending means so as to be responsive to the transverse position of the edges of said web with respect to said signal sending means, said signal receiving means comprising a vane member associated with each of said orices and operated in response to the passage of air through its associated orifice, means adjusting the distance between said signal sending means disposed on each side of the web along a line generally transverse to said centerline, means responsive to signals received by either or both of said signal receiving means controlling said width adjustment of said signal sending means in accordance with varying widths in said web independent of the centering of said web, and means responsive to signals received by both of said signal receiving means indicating the center of said web relative to said centerline.

JOSEPH C. FROMMER.

References Cited in the lle of this patent vUNITED STATES PATENTS Number Name Date 2,078,669 King Apr. 27, 1937 2,117,878 Friedmann May 17, 1938 2,438,787 Nicholas Mar. 30, 1948 2,534,686 Strauss et al. Dec. `19, 1950 2,548,590 Cook Apr. 10, 1951 

